Jeep YJ Wrangler 2.5L Drivability Issues

Hi I'm new here and I hope I'm posting in the right place. I have read numerous forums looking for answers with no avail. But here is my story...I have a 92 yj 2.5l recently purchased. First week I installed new fuel filter, plugs, wires and valve cover. Had new cat and muffler. It sat for a couple years before I got it with 1/4 tank fuel.

I filled it up and drove it about 300 miles with no problems. It started to sputter and lose power as it got low on fuel so I filled it up again with some good fuel and some fuel system treatment. It ran good after that no sputtering or loss of power. Recently I took it out and went off road it ran great. Took it to store shortly after and made uturn and it sputtered and loss of power returned. Gets worse on demand. Shut it off and start back up and runs good for a mile or so then starts bogging and losing power until I shut off and restart.

I replaced fuel pump and drove home, ran great no issues. Later that day I drove to dinner 2 miles away and stopped at store, left running, went to leave store and it started sputtering and was now losing power worse than before almost to a stall, more I push accel more it would bog down almost to seem as if it was stalling out. I would cycle key off and back on and it would run for a mile or less and start losing power again. Today I replaced, tps, o2, cat and rotor, fuel filter, and cleaned intake with sea foam. Once hot it still had same symptoms but now even worse. All help is greatly appreciated.

Hi, 21114yj, and welcome to the forums! There is a long string of discussion on the 2.5L TBI at this Wrangler forum and articles at the magazine. Below are two links to popular articles on troubleshooting 2.5L TBI:

Tune-up and troubleshooting the fuel-and-spark system is crucial to reliable Jeep performance. This section focuses on Jeep engine tuning, including ignition and fuel system troubleshooting, diagnostics and repairs.

Before plunging further into the TBI system, you did clean the fuel tank when you installed the new pump? If there is a pickup restriction, that's always an issue. Sounds like you've already pursued that troubleshooting possibility.

Often overlooked, and the symptoms can mimic a fuel supply problem, there is the epidemic issue of poor electrical grounds on the YJ Wrangler. I would check all of your engine, body and frame ground connections under the hood, in particular the junction near the oil dipstick and the firewall grounds. These are notorious for corroding and creating a voltage drop. On a 12VDC electrical system, grounds are as critical as hot wires.

Make sure the under dash ECU ground is also good. Paint, rust and corrosion each can cause havoc. If the ECU gets false or strange voltage signals, there can be trouble with the fuel supply system, the ignition and so forth. YJ Wrangler drivability issues can frequently be traced to bad electrical grounds.

Let us know what works. Look over the other 2.5L TBI troubleshooting threads at this YJ Wrangler forum. I'll gladly respond if you still have questions.

I have a similar issue 21114yj,luckily my CEL came on. Code 22 came up. Coolant sensor. $15. I am ordering it tomorrow. Its a cheap shot at fixing it. What my friend told me is, the Jeep is dumping more fuel because the sensor is messed up and the Jeep is acting like it is extremely cold outside.

Very logical troubleshooting, lebo7204...A coolant sensor problem can make the engine stay in warm-up, enrichment mode. Certainly worth a try if you're getting that code. Not sure whether 21114jy has a code. Begs investigating, for sure.